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XB-ART-49512
PLoS One January 1, 2014; 9 (10): e110559.

FoxA4 favours notochord formation by inhibiting contiguous mesodermal fates and restricts anterior neural development in Xenopus embryos.

Murgan S , Castro Colabianchi AM , Monti RJ , Boyadjián López LE , Aguirre CE , Stivala EG , Carrasco AE , López SL .


Abstract
In vertebrates, the embryonic dorsal midline is a crucial signalling centre that patterns the surrounding tissues during development. Members of the FoxA subfamily of transcription factors are expressed in the structures that compose this centre. Foxa2 is essential for dorsal midline development in mammals, since knock-out mouse embryos lack a definitive node, notochord and floor plate. The related gene foxA4 is only present in amphibians. Expression begins in the blastula -chordin and -noggin expressing centre (BCNE) and is later restricted to the dorsal midline derivatives of the Spemann''s organiser. It was suggested that the early functions of mammalian foxa2 are carried out by foxA4 in frogs, but functional experiments were needed to test this hypothesis. Here, we show that some important dorsal midline functions of mammalian foxa2 are exerted by foxA4 in Xenopus. We provide new evidence that the latter prevents the respecification of dorsal midline precursors towards contiguous fates, inhibiting prechordal and paraxial mesoderm development in favour of the notochord. In addition, we show that foxA4 is required for the correct regionalisation and maintenance of the central nervous system. FoxA4 participates in constraining the prospective rostral forebrain territory during neural specification and is necessary for the correct segregation of the most anterior ectodermal derivatives, such as the cement gland and the pituitary anlagen. Moreover, the early expression of foxA4 in the BCNE (which contains precursors of the whole forebrain and most of the midbrain and hindbrain) is directly required to restrict anterior neural development.

PubMed ID: 25343614
PMC ID: PMC4208771
Article link: PLoS One

Genes referenced: ag1 chrd.1 egr1 egr2 emx1 emx1l en2 foxa2 foxa4 frzb gsc hes4 hesx1 hoxb1 hoxb7 hoxc6 myf5 myod1 nog otx2 shh six3 slc5a5 sox2 tbxt tubb2b
Morpholinos: foxa4 MO1


Article Images: [+] show captions
References:
Acosta, 2011, Pubmed, Xenbase [+]


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